I have a sheet of plexiglass that has metal strips (Aluminum) that will be connected through wires to an Arduino. The Arduino is grounded but the metal strips are not. The metal strips will rest on top of plexiglass. I'm wondering how I could ground the metal strips? Is there a material I can place under the metal strips that I can attach ground to in order to reduce interference/cross talk (between the Aluminum strips)?
I'm assuming that you want to use each of the aluminum strips as some sort of input, and to have them pulled low by default. If that's the case, connect each strip to one of the GND pins of the arduino with a 10kohm resistor (or something in that ballpark), one resistor per aluminum strip. This will pull each strip low while still allowing a high signal to be applied through them.